armpit, underarm region
PYRAMID of the axilla
base is the skin and fascia of underarm
1. ANTERIOR WALL--PECTORALIS MAJOR
2. POSTERIOR WALL--LATISSIMIS DORSI
3. MEDIAL WALL--SERRATUS ANTERIOR
4. APEX--HEAD OF HUMERUS - top of pyramid
FOLDS of the axilla- there are 2 folds
1. ANTERIOR FOLD: PECTORALIS MAJOR - inferior border of pectoralis major.
2. POSTERIOR FOLD: LATISSIMIS DORSI & TERES MAJOR -
3. FOLDS MEET AT INTERTUBERCULAR GROOVE OF THE HUMERUS
1. AXILLARY ARTERY - continuation of subclavian artery. It changes names to axillary as it crosses landmarks.
a) BEGINS AS IT CROSSES 1ST RIB
2. AXILLARY VEIN
a) DRAINS INTO SUBCLAVIAN VEIN AT DELTOPECTORAL TRIANGLE
b) CEPHALIC VEIN DIVES THROUGH THE DELTOPECTORAL TRIANGLE TO DRAIN INTO AXILLARY VEIN.
3. BRACHIAL PLEXUS
a) NERVE PLEXUS THAT SUPPLIES THE UPPER EXTREMITY WITH SENSORY AND MOTOR INNERVATION
4. AXILLARY LYMPH NODES - mixed in with the fascia. Most will be torn out with the fascia and not know it because in dead tissue on the cadaver the color blends in. Look like a kidney bean (similar to renal shape). Small - smaller than a centimeter. Occasionally they are enlarged due to a specific pathology.
5. FAT the body packs fat wherever it has spaces. Must use blunt dissection to preserve all the other structures.
Define the SCAPULA by it's borders and angles.
A. THREE (3) BORDERS
B. THREE (3) ANGLES
3. LATERAL-GLENOID FOSSA -
a) HEAD OF THE HUMERUS ARTICULATES
Define the spine of the scapula.
1. ON POSTERIOR SURFACE
2. ACROMION IS THE DISTAL PART OF THE SPINE - acromion actually sweeps pretty far forward and can see from anterior view as well. Articulates with clavicle.
CORACOID PROCESS - looks like a finger projecting anteriorly out deep to the clavicle. For muscle attachment.
What are THREE (3) FOSSAE on Scapula?
THREE (3) FOSSAE on Scapula
1. SUPRASPINOUS - depression on superior of spine
2. INFRASPINOUS - depression on inferior side of the spine
3. SUBSCAPULAR - on anterior surface, fills whole anterior surface of the scapula. "sub" meaning the deep surface too the back.
Define the suprascapular notch of scapula.
SUPRASCAPULAR NOTCH - along superior border. Notches often connect to ligaments. (Glenoid Fossa) A ligament attaches to convert this notch into a foramen that has an artery and a nerve coming through it.
1. SUPRASCAPULAR NERVE AND ARTERY
What does the scapula articulate with?
ARTICULATES ONLY WITH THE CLAVICLE AND THE HUMERUS - acromial clavicular joint - synovial joint, planar (gliding), tied together with ligaments so very little motion. Gelohumeral joint between head of the humerous and the glenoid fossa. 2. BONE FLOATS OVER THE RIB CAGE. IT CAM BE MOVED ANTERIORLY, POSTERIORLY, SUPERIORLY, INFERIORLY, AND ROTATED.
How does the clavicle articulate with the sternum?
A. STERNAL EXTREMITY - articulates with sternum
B. ACROMIAL EXTREMITY - articulates with the acromion. A tubricle sits on the underside for a muscle attachment.
What type of joint is the STERNOCLAVICULAR JOINT?
STERNOCLAVICULAR JOINT - only bone to bone contact of the pectoral girdle with the axial skeleton.
1. COMPLEX JOINT
a) MENISCUS - complex synovial joint
What are the ligaments of the STERNOCLAVICULAR JOINT?
2. LIGAMENTS - not a lot of motion b/c so many ligaments holding it down. Don't want a lot of motion b/c this is the only joint in the pectoral girdle.
a) ANTERIOR STERNOCLAVICULAR LIGAMENT -
b) POSTERIOR STERNOCLAVICULAR LIGAMENT
c) INTERCLAVICULAR LIGAMENT - runs from one clavicle to the other through the sternal notch
d) COSTOCLAVICULAR LIGAMENT-on each side goes from the first rib to the clavicle.
What type of joint is the ACROMIOCLAVICULAR JOINT?
ACROMIOCLAVICULAR JOINT is a PLANE TYPE OF SYNOVIAL JOINT - planar joint held together by lots of ligaments.
What are the ligaments of the ACROMIOCLAVICULAR JOINT?
a) ACROMIOCLAVICULAR LIGAMENT -from acromion to clavicle
b) CORACOCLAVICULAR LIGAMENT- composed of two parts. Both originate on the coracoid and go to the clavicle.
(1) TRAPEZOID LIGAMENT
(2) CONOID LIGAMENT
c) CORACOACROMIAL LIGAMENT- connects to parts of the same bone. That ligament is helping to form part of the socket for the shoulder joint. Glenoid is a very shallow fossa, almost flat. Ball and socket joint. Ball head of humerous can fit into socket, but lots of motion b/c such a shallow socket. Glenoid Labrum = Lip of fibrocartiledge that helps deepen the socket.
What type of joint is the GLENOHUMORAL JOINT?
1. BALL AND SOCKET SYNOVIAL JOINT
a) MOVEMENT IN ALL THREE AXES
b) GLENOID LABRUM
What are the ligaments of the GLENOHUMORAL JOINT?
GLENOHUMORAL JOINT LIGAMENTS
a) GLENOHUMERAL LIGAMENTS
(1) SUPERIOR, MIDDLE AND INFERIOR
b) TRANSVERSE HUMERAL LIGAMENT - runs from greater tuberosity to lesser tuberosity and bridges over the intertubicular groove. Tendon of bicepts brachii goes through the interubicular tube and attaches.... Holds the tendon in place.
c) CORACOHUMERAL LIGAMENT
d) CORACOACROMIAL LIGAMENT- makes a socket for the head of the humerous. Strange joint b/c so little bone to bone contact. Tremendous range of motion but unstable - easy to dislocate the shoulder.
WHAT IS A BURSA?
BURSAE - like a synovial membrane without the bones. A little sac or bag secreting synovial fluid. Bursae are in places where muscles or tendons rub against other muscles or bones. Has a shiny inner surface due to fluid lubricant.
What are the bursa associated with the scapula?
SUBSCAPULAR - bursae sits between scapula and ribs. Allows scapula to move freely across itself. Synovial fluid is lubrication.
b) SUBACROMIAL/SUBDELTOID sac deep to the deltoid and acromion sitting superior to the humerous & supraspinatous muscle. Joint that commonly gets "bursitis" - inflammation of the bursa. Hurts because of swelling in the combined space which puts pressure on the nerves and causes pain.
What are the 6 SUPERFICIAL MUSCLES associated with the axillary region?
2. LATISSIMIS DORSI
3. TERES MAJOR
4. STERNOCLEIDOMASTOID (STERNOMASTOID)
5. PECTORALIS MAJOR
Why is the trapezius named as such?
TRAPEZIUS - named because when you look at both sides together it looks like a trapezoid.
What is the origin of the trapezius?
ORIGIN: EXTERNAL OCCIPITAL PROTUBERANCE, SUPERIOR NUCHAL LINE, LIGAMENTUM NUCHAE, SPINES OF C7-T12 Origin from midline structures at base of skull at superior occipital protuberance to bottom of the thorax. Ligamentum Nuchae is the connective tissue ligament running from edges of spine of cervical vertebrae up the spine and serves as muscle attachment. Below that, trapezius takes origin from the spines of C7-T12.
What is the insertion of trapezius?
INSERTION: SPINE AND ACROMION OF THE SCAPULA, DISTAL 1/3 OF THE CLAVICLE. - comes over to the scapula and attaches to the spine and acromion of the scapula and the distal third of the clavicle.
What is the action of trapezius?
ACTION: ELEVATES, RETRACTS (ADDUCTS), AND DEPRESSES THE SCAPULA - very large muscle. Actions are a little complicated. Can stimulate parts to contract, not the whole thing at a time. If you stimulate the upper parts, it elevates the scapula. If you stimulate the lower part, it depresses the scapula. Trapezius thus works as its own antagonist. Middle adducts/retracts the scapula.
What is the innervation of trapezius?
INNERVATION: THE ACCESSORY NERVE (XI) - spinal accessory nerve cranial nerve XI (eleven) innervates trapezius. It comes out of the skull and innervates sternocleidomastoid first, and then goes posterior to innervate trapezius and runs on the underside of trapezius. Generally nerves supplying muscles are on the underside (deepside) of the muscles, which provides some protection for the nerve.
What is the origin of LATISSIMUS DORSI?
ORIGIN: SPINES OF T7-T12, THORACOLUMBAR FASCIA, ILIAC CREST AND RIBS 8-12. - Origin is primarily from the thoracolumbar fascia. Lats run to the iliac crest to the sacrum and up to the spine of the lumbar vertebrae. The lat is deep to the trap up top and takes origin from T-7 - T12 and also from ribs 8-12.
What is the insertion of Latissimus Dorsi?
INSERTION: INTERTUBERCULAR GROOVE OF THE HUMERUS - Wraps around side and inserts on medial lip of intertubercular groove in armpit. Groove between the greater and lesser tubricle of humerus. It is also called bicepital groove.
What is the action of Latissimus Dorsi?
ACTION: EXTENDS, ADDUCTS AND MEDIALLY ROTATES HUMERUS. - Extends humorous up. On medial side so strong adductor. When it contracts it also rotates the arm medially.
What is the innervation of Latissimus Dorsi?
INNERVATION: THORACODORSAL NERVE - one of the nerves derived from the brachial plexus.
Why is Teres Major named as such?
TERES MAJOR - Teres means round. It feels round in cross section. Major means it is the largest of the round muscles there.
What is the origin of Teres Major?
ORIGIN: INFERIOR ANGLE OF THE SCAPULA - on lateral side
What is the insertion of Teres Major?
INSERTION: INTERTUBERCULAR GROOVE OF THE HUMERUS - inserts along with latissimus
What is the action of Teres Major?
ACTIONS: ADDUCTS AND MEDIALLY ROTATES ARM - like latissimus
What is the innervation of Teres Major?
INNERVATION: LOWER SUBSCAPULAR NERVE - one of the nerves of the brachial plexus
Why is the sternocleidomastoid named as such?
STERNOCLEIDOMASTOID (STERNOMASTOID) - named for attachments. Originates at sternum and clavical and inserts on the mastoid process. Muscle of the neck.
What is the origin of sternocleidomastoid?
ORIGIN: BY TWO HEADS FROM STERNUM AND CLAVICLE
What is the insertion of sternocleidomastoid?
INSERTION: MASTOID PROCESS OF TEMPORAL BONE
What is the action of sternocleidomastoid?
ACTION: ELEVATES AND ROTATES HEAD
What is the innervation of sternocleidomastoid?
INNERVATED BY XI - accessory nerve. Cranial Nerve XI
What is the origin of pectorals major?
a) CLAVICULAR HEAD: MEDIAL HALF OF THE CLAVICLE
b) STERNOCOSTAL HEAD: STERNUM, SUPERIOR 6 COSTAL CARTILAGES, EXTERNAL OBLIQUE APONEUROSIS-
What is the insertion of pectoralis major?
INSERTION: INTERTUBERCULAR GROOVE OF THE HUMERUS - lat and teres major insert on medial border. Pec Major goes over them and inserts on the lateral border of the intertubercular groove.
What is the action of pectoralis major?
ACTION: ADDUCTS AND MEDIALLY ROTATES HUMERUS, AIDS IN FLEXING THE SHOULDER JOINT (like bench press position or peck deck)
What is the innervation of pectoralis major?
INNERVATION: BOTH MEDIAL AND LATERAL PECTORAL NERVES - these two nerves are positioned in the body with the names flipped. The Medial nerve sits laterally. The Lateral Nerve sits medial. This is become they come from the chord of the brachial plexus. The medial nerve comes from the medial chord of the brachial plexus through pectoralis minor. Lateral pec nerve does not touch pec minor and comes from the lateral chord of the plexus.
What is the origin of deltoid?
ORIGIN: LATERAL THIRD OF CLAVICLE, ACROMION, AND SPINE OF THE SCAPULA - takes origin from same spot as insertion of trapezius
What is the insertion of deltoid?
INSERTION: DELTOID TUBEROSITY OF HUMERUS
What are the actions of deltoid?
ACTIONS: FLEXES AND MEDIALLY ROTATES ARM (ANTERIOR PART); ABDUCTS ARM (MIDDLE PART); AND EXTENDS AND LATERALLY ROTATES ARM (POSTERIOR PART) - cannot abduct until the arm is already out 30 degrees from the body. Abducts from middle of muscle. Like trapezius, it depends on which part of the muscle being use for what it does.
What is the innervation of deltoid?
INNERVATION: AXILLARY NERVE - part of brachial plexus
Which bursa is associated with deltoid?
What are the DEEP MUSCLES, i.e. the MUSCLES ATTACHING PECTORAL GIRDLE TO AXIAL SKELETON?
1. RHOMBOID MAJOR
2. RHOMBOID MINOR
3. LEVATOR SCAPULAE
4. SERRATUS ANTERIOR
5. PECTORALIS MINOR
Why is the Rhomboid named as such?
RHOMBOID (MAJOR AND MINOR) - still considered superficial, but it lies deep to trapezius. Really one big muscle that gets separated. Named b/c look like a rhomboid.
What is the origin of the rhomboid?
a) MAJOR: SPINES OF T2-T5
b) MINOR: SPINES OF C7 & T1 - small part superior
What is the insertion of the rhomboid?
INSERTION: MEDIAL (VERTEBRAL) BORDER OF THE SCAPULA - they run down at angle
What is the action of the rhomboid?
ACTION: RETRACT (ADDUCT) SCAPULA, ROTATES SCAPULA TO DEPRESS THE GLENOID CAVITY, FIXES SCAPULA TO THE THORACIC WALL - torques/rotates scapulae so glenoid will rotate inferiorly. Find this motion when add/abducting the humerous = inferior rotation. Rohmboids hold the scapula to the body by attaching it to the spine.
What is the innervation of the rhomboid?
INNERVATION: DORSAL SCAPULAR NERVE - nerve derived from the brachial plexus.
What is the origin of the levator scapulae?
ORIGIN: TRANSVERSE PROCESSES OF C1-C4 -
What is the insertion of the levator scapulae?
INSERTION: SUPERIOR ANGLE OF THE SCAPULA
What is the action of the lavator scapulae?
ACTION: ELEVATES AND ROTATES THE SCAPULA SO THAT THE GLENOID FOSSA TURNS INFERIORLY - assists trapezius in elevating the scapula.
What is the innvervation of the levator scapulae?
INNERVATION: DORSAL SCAPULAR NERVE AND C3 & C4 - part of anterior rami of C3-C4 b/c they run through the muscle.
What is the serratus anterior?
SERRATUS ANTERIOR - accessory muscle of respiration, pulls the ribs up and out to expand the rib cage. Used when other muscles of respiration are tired.
What is the origin of the serratus anterior?
ORIGIN: RIBS 1-8 - originates on side from first 8 ribs. Wraps around the ribcage and inserts on the deep side of the medial border of the scapula.
What is the insertion of the serratus anterior?
INSERTION: MEDIAL (VERTEBRAL) BORDER OF THE SCAPULA
What is the action of the serratus anterior?
ACTION: PROTRACTS (ABDUCTS) SCAPULA, HOLDS SCAPULA AGAINST THORACIC WALL, ROTATES SCAPULA.
What is the innervation of the serratus anterior?
INNERVATION: LONG THORACIC NERVE (VIA BRACHIAL PLEXUS) -fairly superficial nerve on side of thorax. If damaged, the person's medial border of the scapula will jut out.
What is the origin of the pectoralis minor?
ORIGIN: RIBS 3-5
What is the insertion of pectoralis minor?
INSERTION: CORACOID PROCESS OF THE SCAPULA -(does not insert on the humorous)
What is the action of pectoralis minor?
ACTION: DEPRESSES SCAPULA, ROTATES IT INFERIORLY, PULLS SCAPULA ANTERIORLY - helps seratus when protracting to pull around anteriorly.
What is the innervation of pectoralis minor?
INNERVATION: MEDIAL PECTORAL NERVE
What is the subclavius?
SUBCLAVIUS - shock absorber. As motion pulls the arm away from the sternum, it takes up tension to take strain off of ligaments... but a pretty small muscle.
What is the origin of SUBCLAVIUS?
ORIGIN: 1ST RIB
What is the insertion of SUBCLAVIUS?
INSERTION: INFERIOR SURFACE OF MIDDLE THIRD OF THE CLAVICLE
What is the action of SUBCLAVIUS?
ACTION: DRAWS CLAVICLE MEDIALLY
What is the innervation of SUBCLAVIUS?
INNERVATION: NERVE TO SUBCLAVIUS
What is the CLAVIPECTORAL FASCIA?
CLAVIPECTORAL FASCIA - contains the axial. (fascia can contain infection)
What are the ROTATOR CUFF MUSCLES?
1. SUPRASPINATUS- named for origin
2. INFRASPINATUS - named for origin
3. TERES MINOR
4. SUBSCAPULARIS - deep side of scapula
What is the origin of SUPRASPINATUS?
ORIGIN: SUPRASPINOUS FOSSA OF SCAPULA
What is the insertion of SUPRASPINATUS?
INSERTION: GREATER TUBERCLE OF THE HUMERUS
What is the action of SUPRASPINATUS?
ACTION: ABDUCTION OF HUMERUS, COMMON ACTION OF ROTATOR CUFF MUSCLES -gets arm 30 degrees out before deltoid can abduct. This muscle is the one of four that doesn't rotate.
What is the innervation of SUPRASPINATUS?
INNERVATION: SUPRASCAPULAR NERVE
What is the origin of INFRASPINATUS?
ORIGIN: INFRASPINOUS FOSSA OF SCAPULA
What is the insertion of INFRASPINATUS?
INSERTION: GREATER TUBERCLE OF HUMERUS- a little more posterior
What is the action of INFRASPINATUS?
ACTION: LATERALLY ROTATE HUMERUS, COMMON ACTION OF ROTATOR CUFF MUSCLES
What is the innervation of INFRASPINATUS?
INNERVATION: SUPRASCAPULAR NERVE
What is the origin of TERES MINOR?
ORIGIN: LATERAL BORDER OF THE SCAPULA
What is the insertion of TERES MINOR?
INSERTION: GREATER TUBERCLE OF THE HUMERUS - next to infraspinatus.
What is the action of TERES MINOR?
ACTION: LATERALLY ROTATE HUMERUS, COMMON ACTION OF ROTATOR CUFF MUSCLES
What is the innervation of TERES MINOR?
INNERVATION: AXILLARY NERVE
What is the origin of SUBSCAPULARIS?
ORIGIN: SUBSCAPULAR FOSSA
What is the insertion of SUBSCAPULARIS?
INSERTION: LESSER TUBERCLE OF THE HUMERUS - comes around to attach on anterior side of humorous.
What is the action of SUBSCAPULARIS?
ACTION: MEDIAL ROTATE AND ADDUCTS ARM, COMMON ACTION OF ROTATOR CUFF MUSCLES
What is the innervation of SUBSCAPULARIS?
INNERVATION: UPPER AND LOWER SUBSCAPULAR NERVES
What is the COMMON ACTION OF ROTATOR CUFF MUSCLES?
COMMON ACTION OF ROTATOR CUFF MUSCLES
- When they contract together they bring the humorous up into the glenoid fossa. These muscles are the main stabilizers of this joint for the humorous.
What are the 3 processes of the scapula?
b) ACROMION (ACROMIAL PROCESS)
c) CORACOID PROCESS
What are the 4 Fossae of the scapula?
d) GLENOID - points of attachment for big muscles
(1) SUPRAGLENOID TUBERCLE - top of glenoid
(2) INFRAGLENOID TUBERCLE
What are the 3 features of the clavicle?
1. STERNAL EXTREMITY
2. ACROMIAL EXTREMITY
3. CONOID TUBERCLE - point where subclavious attaches
What are the 14 anatomical features of the humerus?
2. ANATOMICAL NECK
3. SURGICAL NECK
4. GREATER TUBERCLE
5. LESSER TUBERCLE
6. INTERTUBERCULAR GROOVE
7. DELTOID TUBEROSITY
8. RADIAL GROOVE/SULCUS
11. Olecranon Fossa
12. LATERAL EPICONDYLE
13. MEDIAL EPICONDYLE
14. SUPRACONDYLEAR RIDGES
What is the HEAD of the humerus?
HEAD - what articulates with the glenoid
What is the ANATOMICAL NECK of the humerus?
ANATOMICAL NECK - marks the location of the epiphesial (growth) plate.
What is the SURGICAL NECK of the humerus?
SURGICAL NECK - named b/c place where the humerus is often fractured and needs to be repaired by "open reduction" surgery using screws, etc.
What is the GREATER TUBERCLE of the humerus?
GREATER TUBERCLE - attachment for rotator cuff
What is the LESSER TUBERCLE of the humerus?
LESSER TUBERCLE - attachment of rotator cuff
What is the INTERTUBERCULAR GROOVE of the humerus?
INTERTUBERCULAR GROOVE - (bicipital groove) tendon of biceps runs in that groove.
What is the DELTOID TUBEROSITY of the humerus?
DELTOID TUBEROSITY - in middle of shaft of humerus lower than many people think. Attachment for deltoid muscle.
What is the RADIAL GROOVE/SULCUS of the humerus?
RADIAL GROOVE/SULCUS - shallow groove that radial nerve (from brachial plexus) is found sitting in. Hard to see, but you can feel it as a spiral groove that wraps around.
What is the TROCHLEA of the humerus?
TROCHLEA - distal end of humerus. Groove goes about 300 degrees to wrap around. Looks like a pulley. Pulley in latin = Trochlea. For articulation of Ulna
What is the CAPITULUM of the humerus?
CAPITULUM - head in latin = "capit". Capitulum means little head. For articulation with the radius. Rounded.
What is the Olecranon Fossa of the humerus?
Olecranon Fossa - posterior receives olecranon process of ulna. Fits into fossa when elbow is fully extended. This stops the elbow from hyperextending.
What is the LATERAL EPICONDYLE of the humerus?
LATERAL EPICONDYLE - bump on lateral side
What is the MEDIAL EPICONDYLE of the humerus?
MEDIAL EPICONDYLE - (epicondyle = bump on a condyle) on medial side (for muscle attachment)
What is the SUPRACONDYLEAR RIDGES of the humerus?
SUPRACONDYLEAR RIDGES - for muscle attachment
What are the 7 anatomical features of the ULNA?
1. HEAD (DISTAL)
2. STYLOID PROCESS
3. OLECRANON PROCESS
4. CORANOID PROCESS
5. TROCHLEAR NOTCH
6. RADIAL NOTCH
What is the HEAD of the ULNA?
HEAD (DISTAL) - head is distal end **** (this usually confuses people) backwards of every other bone in the body. It is rounded. Can palpate.
What is the STYLOID PROCESS of the ULNA?
STYLOID PROCESS - needle like process on the medial edge of the head.
What is the OLECRANON PROCESS of the ULNA?
OLECRANON PROCESS - forms point of elbow on proximal end.
What is the CORANOID PROCESS of the ULNA?
CORANOID PROCESS - The coronoid process is a triangular eminence projecting forward from the upper and front part of the ulna.
What is the TROCHLEAR NOTCH of the ULNA?
TROCHLEAR NOTCH - fits into the trochlea of the humerus. Mirror image of the trochlea and they fit together.
What is the RADIAL NOTCH of the ULNA?
RADIAL NOTCH - on lateral edge of proximal end where head of radius sits to articulate with the ulna. Can't see very well in picture b/c radius is articulating in the notch.
What is the TUBEROSITY of the ULNA?
TUBEROSITY - proximal anterior surface. For brachialas muscle attachment.